base64.h

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/* -*- c++ -*- */
/*
 * gr-satnogs: SatNOGS GNU Radio Out-Of-Tree Module
 *
 *  Copyright (C) 2019, Libre Space Foundation <http://libre.space>
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
/*
 base64.cpp and base64.h
 base64 encoding and decoding with C++.
 Version: 1.01.00
 Copyright (C) 2004-2017 René Nyffenegger
 This source code is provided 'as-is', without any express or implied
 warranty. In no event will the author be held liable for any damages
 arising from the use of this software.
 Permission is granted to anyone to use this software for any purpose,
 including commercial applications, and to alter it and redistribute it
 freely, subject to the following restrictions:
 1. The origin of this source code must not be misrepresented; you must not
 claim that you wrote the original source code. If you use this source code
 in a product, an acknowledgment in the product documentation would be
 appreciated but is not required.
 2. Altered source versions must be plainly marked as such, and must not be
 misrepresented as being the original source code.
 3. This notice may not be removed or altered from any source distribution.
 René Nyffenegger rene.nyffenegger@adp-gmbh.ch
 */
 
#ifndef INCLUDE_SATNOGS_BASE64_H_
#define INCLUDE_SATNOGS_BASE64_H_
 
#include <iostream>
 
static const std::string base64_chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
                                        "abcdefghijklmnopqrstuvwxyz"
                                        "0123456789+/";
 
static inline bool is_base64(unsigned char c)
{
    return (isalnum(c) || (c == '+') || (c == '/'));
}
 
static std::string base64_encode(unsigned char const* bytes_to_encode,
                                 unsigned int in_len)
{
    std::string ret;
    int i = 0;
    int j = 0;
    unsigned char char_array_3[3];
    unsigned char char_array_4[4];
 
    while (in_len--) {
        char_array_3[i++] = *(bytes_to_encode++);
        if (i == 3) {
            char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
            char_array_4[1] =
                ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4);
            char_array_4[2] =
                ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6);
            char_array_4[3] = char_array_3[2] & 0x3f;
 
            for (i = 0; (i < 4); i++) {
                ret += base64_chars[char_array_4[i]];
            }
            i = 0;
        }
    }
 
    if (i) {
        for (j = i; j < 3; j++) {
            char_array_3[j] = '\0';
        }
 
        char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
        char_array_4[1] =
            ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4);
        char_array_4[2] =
            ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6);
 
        for (j = 0; (j < i + 1); j++) {
            ret += base64_chars[char_array_4[j]];
        }
 
        while ((i++ < 3)) {
            ret += '=';
        }
    }
 
    return ret;
}
 
static std::string base64_decode(std::string const& encoded_string)
{
    size_t in_len = encoded_string.size();
    int i = 0;
    int j = 0;
    int in_ = 0;
    unsigned char char_array_4[4], char_array_3[3];
    std::string ret;
 
    while (in_len-- && (encoded_string[in_] != '=') && is_base64(encoded_string[in_])) {
        char_array_4[i++] = encoded_string[in_];
        in_++;
        if (i == 4) {
            for (i = 0; i < 4; i++) {
                char_array_4[i] = base64_chars.find(char_array_4[i]) & 0xff;
            }
 
            char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);
            char_array_3[1] =
                ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);
            char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3];
 
            for (i = 0; (i < 3); i++) {
                ret += char_array_3[i];
            }
            i = 0;
        }
    }
 
    if (i) {
        for (j = 0; j < i; j++) {
            char_array_4[j] = base64_chars.find(char_array_4[j]) & 0xff;
        }
 
        char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);
        char_array_3[1] =
            ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);
 
        for (j = 0; (j < i - 1); j++) {
            ret += char_array_3[j];
        }
    }
 
    return ret;
}
 
#endif /* INCLUDE_SATNOGS_BASE64_H_ */